Materials / Compare
Plastic PEEK vs. Plastic PPS GF40
Compare Plastic PEEK vs. Plastic PPS GF40 strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 98MPasourcetypical, tensile yield | not given (tensile used) |
| Ultimate tensile strength | not sourced | 195MPasourcetensile strength, 5 mm/min |
| Compressive strength | 125MPasourcetypical, 23 C | not sourced |
| Flexural strength | 165MPasourcetypical, flexural stress at yield, 23 C | 285MPasourceflexural strength at break |
| Elongation at break | 25%sourcetypical, at break | 1.9%sourcestrain at break, 5 mm/min |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | 14.7GPasourcetypical, 1 mm/min |
| Density | 1,300kg/m³sourcetypical (crystalline) | 1,650kg/m³sourcetypical |
| Strength to weight | 75.4kN·m/kg | 118kN·m/kg1.57x higher |
| Stiffness to weight | 3.08MN·m/kg | 8.91MN·m/kg2.9x higher |
| Poisson's ratio | 0.38sourcetypical | 0.35sourceglass-reinforced Fortron PPS (class value, not grade-specific) |
| Shear modulus | 1.45GPa | 5.44GPa3.76x stiffer in shear |
| Bulk modulus | 5.56GPa | 16.3GPa |
| Speed of sound | 1,754m/s | 2,985m/s |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 0.2W/m·Ksource40% glass-reinforced Fortron, 25 °C (not grade-specific) |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | 12µm/m·Ksourceparallel (flow), mean -50 to 90 °C |
| 100 mm part over a 50 °C swing | 275µm growth | 60µm growth4.58x less |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | not sourced |
| Heats up and cools (diffusivity) | 0.101mm²/s | not sourced |
| Thermal shock resistance | 80.1W/m | 144W/m1.79x more resistant |
| Melting point | 343°Csourcetypical, DSC | 280°CsourceDSC, 10 °C/min |
| Glass transition | 143°Csourceonset (midpoint 150 C) | 90°CsourceDSC, 10 °C/min |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | 270°CsourceHDT 1.8 MPa |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | Celanese Fortron 1140L4 (PPS, 40% glass fibre), injection moulding; FORTRON PPS Short-Term Properties Guide (PPS-012, 2016); thermal conductivity and Poisson for 40% glass-reinforced Fortron from the Fortron PPS Design Manual (PPS-050, 2013). |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Plastic PEEK stronger than Plastic PPS GF40?
Plastic PPS GF40 is stronger: its tensile strength is 195 MPa against yield strength 98 MPa for Plastic PEEK (1.99x).
Which is lighter, Plastic PEEK or Plastic PPS GF40?
Plastic PEEK is lighter: 1,300 kg/m³ against 1,650 kg/m³ for Plastic PPS GF40.
Which is stiffer, Plastic PEEK or Plastic PPS GF40?
Plastic PPS GF40 is stiffer: Young's modulus 14.7 GPa against 4 GPa for Plastic PEEK, so the same part in Plastic PPS GF40 deflects less under the same load.
Which is lighter for the same job, Plastic PEEK or Plastic PPS GF40?
For the same stiffness or strength: Plastic PPS GF40 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic PEEK | Plastic PPS GF40 |
|---|---|---|
| Stiff rod or tie (tension) | 2.9x heavier | lighter |
| Stiff beam (bending) | 1.51x heavier | lighter |
| Stiff panel or plate | 22% heavier | lighter |
| Strong rod or tie | 1.57x heavier | lighter |
| Strong beam | 25% heavier | lighter |
| Strong panel or plate | 11% heavier | lighter |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Plastic PEEK or Plastic PPS GF40?
Plastic PEEK conducts heat better: 0.29 W/m·K against 0.2 W/m·K for Plastic PPS GF40.
Which expands less with temperature?
Plastic PPS GF40 expands less: 12 µm/m·K against 55 µm/m·K for Plastic PEEK.